Method of tuning.



PATBNTED JUNE 16, 1908.

- M. L. SEVERY & e. B, SINCLAIR.

METHOD OF TUNING.

- APPLICATION FILED AUG. 7.1905.

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Melvin L. Sea/w y, Kfifi ja L fl fl I George B. Sinclair in Methods of Tuning, of which the following l UNITED srATEs aTENT OFFICE.

MELVIN L. SEVERY,'OF ARLINGTON HEIGHTS, AND GEORGE B. SINCLAIR, OF INTI-IROP,

MASSACHUSETTS, ASSIGNORS TO CHORALOELO RATION OF MAINE.

MANUFACTURING COMPANY, A CORPO- METHOD OF TUNING.

Specification of Letters Patent.

' Patented June 16, 1908.

Application filed August 7, 1905. Serial No. 273,204.

T 0 all whom it may concern: l Be it known that we, MELVIN L. SEVERY and GEORGE B. SINCLAIR, both citizens of the United States, and residents of Arlington Heights, county of Middlesex, and Winthrop, in the county of Suffolk, respectively, in the Commonwealth of Massachusetts, have made certain new and useful Improvements is a full, clear, and exact description The object of this invention 18 the effecting of means whereby a'stringed instrument can be tuned with absolute accuracy, even by a person devoid of what is termed a musical ear, and wholly unskilled in the present art of iano tuning.

ale have discovered string is brought into the field .of an electroniagnet having a definitely timed number of electric pulsations conveyed thereto, and such string is gradually tuned up to vibrate in accord with said pulsations, the instant the same are in exact accord the string Wlll string is in exact, tune.

respond with a markedly pronounced maximum loudness, while if tuned but slightly sharp or flat, the resonance will at once fall off and become much weaker. Furthermore, as the string departs in the slightest de rec from the number of vibrations per unit of time given by the electromagnet, not only does its volume decrease, but the quality of the tone chan es as well. Hence, by pro viding a standarc set of electromagnets and pulsating devices for the piano strings, and then gradually tightening each wire until its magnet fails to further increase its loudness of vibration, the operator can know that the Or if he tightens the wire a trifle too much, as evidenced by its diminution in loudness, he loosens up thereon until again the maximum volume is reached. When the operator becomes more experi: enced, he can also detect the exact point by noting the change in quality of sound produced.

In carrying our invention into effect for ordinary pianos or other stringed instrument,

all that is needed in the way of apparatus is a single electromagnet, and a device for imparting thereto any desired number of standard pulsations. Such magnet being supported in close proximity to any one of the strings, and the electric pulsations appropriate to the string communicated to the magnet, all that the tuner needs to do is to that when .a piano tuned in the usual tighten u or loosen such wire until its maximum lom ness and proper quality are reached.

Then the magnet can be shifted to the neixl string; the pulsations changed in accordance therewith, and the tuning done as before. Our rocess is, however, es ecially designed for e ectric pianos wherein t e strings are vibrated by electromagnets permanently in place. Previous to our invention of this rocess, the method of tuning the strings was that of the old-time piano tuner,to turn the tuning-hammer and strike the note until the latter reached the standard set by the tuning fork; striving to reach .the point where the beats, which showed a near approximation, should wholly cease. As diilerent tuners ears varied in their capacity to detect the exact vanishing point of these beats, it is impossible to-tune all pianos precisely alike, even with the same standard. This, however, is a comparatively insignificant matter in comparison with the inability of even the same tuner to get identical temperaments on two or more pianos, or to duplicate the temperament in the same instru ment when it is re-tuned; for the reason that the question of temperament is one of in:

dividual judgment, of compromise with exact chords.

Prior to our invention, the only known method of tuning electrically actuated pianos was to first changethe tension upon each string until it suited the tuners ear, and then" to time the pulsation producing mechanism until it accorded with the vibrations of the strings. In other words, the pulsation producing device of each string is planned to deliver the proper of time to equal the theoretical number of its strings vibrations. Then the strings are manner, and the pulsation producing motor s eeded up or down until the periodicities t ereof approximate the strings vibrations. This is never satisfactory, however, inasmuch as no man can accurately temper the scale of thepiano twice alike, and much less can two professional tuners make two different instruments with their scales exactly the same, so that the strings are never brought to the precise pitch for which their (pulsation producing mechanism is planne This renders the iano irregular and uneven in tone, and unre iable and uncertain in timbre. By means of our process, however, we are enabled to produce number of impulses per unit an instrument wherein 'not only are the strings tuned into exact accord with the standard established for every note in the entire scale, but wherein the strings vibrate with a maximum volume with a minimum expenditure of c'urrent, and which can be ke t in perfect tune by any erson who will fol ow the simple directions aid down.

Referring to the drawings forming part of this specification, and which show in diagram a means for carrying our process into effect, the reference numeral 10 designates a piano string having a tuning pin 30, and an electromagnet in close proximity thereto. The rotating disk 40 having its periphery divided into alternate sections of conducting and non-conducting material 44, 45, acts inconnection with the brush 3, wire 5, source of electricityfiO, lead-wires 61, 62 and brush 41, to impart to said magnet the desired electric pulsations. 1 and 2 re resent a key and contact by which the pu sations are turned off and on to the magnet. By turning the pin 30, the string is tightened or loosened in the usual manner. In tuning said string, the electric pulsations produced by the currentbreaker and exactly timed by a governing device 7 O, are continuously maintained in the electromagnet 20 while the string is being tightened. As the string a proaches an octave below the set standar it will increase in loudness, and then diminish as the tuning is continued ast, but the quality of the note roduced willhnake it evident that the string as not reached the true pitch for which it is desi ned. So the tightening is continued unti a second marked increase in loudness and a richness of quality in the note produced, prove that the string has reached the set pitch. Should the tuning-pin turn slightly too much, the diminution in loudness and quality show instantly that the true point has been assed= This process of tuning is especialy adapted for the electric pianos constructed in accordance with our application Serial No. 273,199.

What we claim as our invention and for which we desire Letters Patent is as follows, to wit;

1. The herein described method of tuning a vibrating magnetically sensitive body. which consists in producing in close proximity to the same, magnetic pulsations corre- 'sponding to the number per unit of time deslgned for such body, and then tuning the latter until it responds to the said magnetic pulsations with its maximum loudness.

2. The herein described method of tuning a vibrating magnetically sensitive body, which consists in producing in close proximity to such body magnetic pulsations corresponding to the number per unit of time of vibrations designed for such body, and then tunin the latter until its loudness and quality 0 sound show it has reached its true pit/Ch. a

In testimony that we claim the foregoing invention, we have hereunto set our hands this 21st day of July, 1905;

MELVIN L. SEVERY. GEORGE B. SINCLAIR. Witnesses:

FRED G. TILTON, A. B. UPHAM. 

